Following an upgrade to Piwik 2.15.0, we began receiving a SCRIPT5: Access is denied error in Internet Explorer 11 for all of our tracked applications that are viewed within an IFrame. We determined that the offending code was in piwik.js on line 38, column 203. The offending code is below:

function o(){if(z(J.frameElement)){return(J.frameElement&&String(J.frameElement.nodeName).toLowerCase()==="iframe")}try{return J.self!==J.top}catch(Y){return true}}

We've replaced the function's code with return true; as a temporary fix. When IE experiences this error it halts any further execution within the file and this results in no tracking being performed. I can confirm that the issue still exists in 2.16.0 and 2.16.1 as well. I should reiterate this only happens in IE and only for applications viewed within an IFrame.